Restraint systems are used in various applications including child restraint systems for a vehicle, restraint systems for cargo loaded upon a pallet, etc.
The prior art includes various types of child safety seats, including rear-facing infant seats which may or may not include a removable base, convertible seats which may be rear or forward-facing, forward-facing only seats, high-back booster seats with a five-point harness, and belt positioning booster seats, for example. Initially, the various child restraint systems were designed to be used with the seatbelts of a vehicle, which seatbelts were originally developed for adult passengers. The prior art seatbelts include lap belts and three-point belts. With the many types of child restraint seats and the various manufacturers, one of the problems with installing child restraint seats properly has always been the incompatibility between the child restraint seat and the vehicle belt system.
To address the incompatibility and to arrive at a standard, various countries are implementing legislation to provide guidelines as to a system to be installed in vehicles for the securing of child restraint seats.
The lower anchor and tethers for children (LATCH) system was designed to make installation of child safety seats easier by requiring child safety seats to be installed without using the vehicles seat belt system. The system requires all new forward-facing child safety seats (not including booster seats) to meet stricter head protection requirements, which calls for a top tether strap. The top tether strap is adjustable via an adjuster and is attached to the back of a child safety seat. The strap includes a hook for securing the child safety seat to a tether anchor found on the rear shelf area of the vehicle or, in the case of mini-vans and station wagons, on the rear floor or on the back of the rear seat of the vehicle. In addition to the tether anchor, the system requires two rear seating positions of all cars, mini-vans and light trucks to become equipped with lower child safety seat anchorage points located at the seat bight, i.e., between the vehicle's seat cushion and the vehicle's seat back. Further, the system requires that all child safety seats will have two attachments which will connect to the vehicle's lower anchorage attachment points. Together, the lower anchors and upper tethers make up the LATCH system.
In accordance with the LATCH system, a child restraint seat is secured to the lower anchor of a vehicle with two clips or hooks. The hooks are coupled to the child restraint seat via a belt or webbing which either extends from each hook to a secured point on the child restraint seat, or via webbing which extends through the structure of the child restraint seat. The belt is adjustable by means of a belt adjuster.
The prior art suffers several disadvantages. For example, current adjuster devices for lower anchor and upper tether assemblies rely on the webbing or belt tension to lock. The greater the tension or load on the belt, the more difficult for the user to release the tension in the belt system. In addition, a prior art cam adjuster with a serrated edge cuts the belt when high loads are imposed in the belt.